This one-of-a-kind experiment has been given full approval by Ontario to proceed, and been underway since the spring of 2001. It addresses a need for research that will be useful to the Canadian Council of Ministers of the Environment (CCME) and the United States Environmental Protection Agency (USEPA) for setting regulations on emission levels of mercury to the atmosphere by electrical utilities and others. This is a unique experiment of international scope that can only be carried out at the Experimental Lakes Area, where whole-ecosystems can be manipulated to give understanding of environmental stressors at the ecosystem level.